board/orangepi/orangepi-r1/genimage.cfg: use correct partition type

The boot partition is not an EFI System Partition, it is a normal FAT
formatted partition, so using type F instead of U makes more sense.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

board/orangepi/orangepi-r1/genimage.cfg

@@ -28,7 +28,7 @@ image sdcard.img {
 	}
 
 	partition boot {
-		partition-type-uuid = U
+		partition-type-uuid = F
 		bootable = "true"
 		image = "boot.vfat"
 	}